Doctor of Philosophy, The Ohio State University, 2019, Materials Science and Engineering

Processing of martensitic steels requires a thermally driven phase transformation into the austenite phase field, where rapid cooling initiates the diffusionless transformation into martensite. The resultant microstructural constituent is a hard, brittle phase that requires subsequent heat treatment to soften the material for optimized mechanical properties. Although the transformation microstructure has the largest influence on these mechanical properties, the prior austenite microstructure has been shown to significantly affect the final product material in the form of ductile to brittle fracture occurrence, classification of creep and cavitation sites, increasing martensite packet and block sizes resulting in Hall-Petch effects, and temper embrittlement. Therefore, reconstruction of the prior austenite phase field can help optimize both the processing of a sample steel or binary ferrous alloy and predicative examinations on the material. However, analysis of the austenite to martensite transformation is hindered by the large volume of noise associated with the transformation. This can be attributed to the scale of the transformation, which results in a single prior austenite grain producing up to 24 martensitic variants; the plasticity associated with the massive formation of martensite; variations in the orientation relationship across variable compositions and morphologies; errors associated with the EBSD-indexing of the transformation microstructure; and annealing twins forming across the prior austenite microstructure. Due to the inherent noise associated with the transformation, modern reconstruction algorithms using point-to-point or flood-fill algorithms struggle to produce accurate and consistent reconstructions of the austenite microstructure. We therefore propose a probabilistic approach to austenite reconstruction in steels and ferrous alloys based on the graph cutting algorithm. This technique can be applied to a number of inverse problems in mate (open full item for complete abstract)

Committee: Stephen Niezgoda PhD (Advisor); Eric Payton PhD (Committee Member); Antonio Ramirez PhD (Committee Member); Yunzhi Wang PhD (Committee Member); Nicholas Brunelli PhD (Committee Member) Subjects: Engineering; Materials Science

MS, University of Cincinnati, 2005, Engineering : Computer Science

The Internet Protocol (IP) is the basic language that all computers use to communicate across networks and the Internet. A flaw in the design of this protocol allows at tackers to forge the sending address of IP packets, known as packet spoofing. This packet spoofing is a serious security issue on networks and the Internet because it prevents authorities from locating the true source of any spoofing attack. In this paper we analyze technologies available for coping with packet spoofing. After this discussion we present a simple method for traceback, followed by an analysis of the method's requirements.

Committee: John Franco (Advisor) Subjects: Computer Science

Doctor of Philosophy, The Ohio State University, 2002, Electrical Engineering

As the size and application domains of the Internet grow explosively during recent years, several new phenomena have been observed and new research issues have emerged in Internet congestion control. In this dissertation, we address these congestion control issues for next-generation Internets with the focus on both the transport and the IP layers. Specifically, we address the following problems: (I) Congestion control of multicast for continuous media applications with the objectives of (weighted) fairness, TCP-friendliness, and scalability. (II) End-host-based, coordinated congestion control of TCP/UDP traffic to enable connections that traverse the same backbone link toshare congestion information and to coordinate among them all the congestion avoidance/control activities. (III) Exploitation of the correlation structure across multiple time scales (and hence the predictability) of Internet traffic for better AQM scheme and TCP congestion control. (IV) Incorporation of protocol effects ignored by previous TCP models in an enhanced TCP model. Design of an AQM controller to stabilize the queue at a router based on the enhanced model. The dissertation is a combination of two synergistic components: design of algorithms/protocols in an analytical framework and their validation with detailed ns-2 simulation and software system building and experiments in FreeBSD on a network testbed.

Committee: Jennifer Hou (Advisor) Subjects:

Master of Science in Electrical Engineering, Cleveland State University, 2010, Fenn College of Engineering

Wireless sensor network applications call for different kinds of network protocols at different levels of the network stack based on application requirements. A number of medium access control (MAC) protocols have been proposed in the literature. Evaluation of most of these MAC protocols have typically been based on simulation, and while such simulation provides interesting insight into the behavior of these protocols, artifacts caused by behavior of hardware is ignored. Further more, MAC protocols are usually evaluated by comparing the new protocol with others based on one or two metrics, the ones that determined the design decisions for the protocol under evaluation. In this thesis, we present a comprehensive evaluation of MAC protocols based on a set of common metrics. The evaluation is conducted by way of experiments on a test bed of real sensor hardware for different scenarios and work loads that would match different application requirements.

Committee: Nigamanth Sridhar PhD (Committee Chair); Chansu Yu PhD (Committee Member); Wenbing Zhao PhD (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2024, Computer Science and Engineering

Wireless meshes offer a resilient and cost-effective framework where multi-hop communication occurs among mesh clients, routers, and gateways. In this framework, computing and communication are essential to guarantee capacity and achieve high performance in terms of network planning, frequency scheduling, and packet routing. In order to optimize the achievable capacity to provide high throughput-latency communication with scalability, adaptivity, and reliability against various network configurations and dynamics, my thesis studies a cross-layer approach, from network infrastructure development to communication schedule and routing path selection, to show that the problem complexity can be managed by decomposition into subproblems via approximation, even learning based solutions. My study in this thesis consists of several approaches: first, we focus on the middle-mile network optimization problem to provide broadband connectivity in rural regions with a theoretical upper bound of infrastructure cost. Second, we investigate channel hopping to achieve high spectrum utilization, interference avoidance, and jamming tolerance. Third, we look into capacity-aware routing using bounded exploration regions to high throughput and reliability with low overhead. Finally, by developing machine learning algorithms using domain knowledge of bounded exploration on the network routing problem, we study the generalizability of the learned routing policies to all uniform random graphs. The middle-mile network optimization is to connect the last-mile networks to the core network service providers with minimal infrastructure cost and throughput constraints. It includes topology construction, tower height assignment, antenna and orientation selection, as well as transmit power assignment, which is known to be a computationally hard problem. We propose the first polynomial time approximation solution for a generalized version of the middle-mile network optimization problem, wherein (open full item for complete abstract)

Committee: Anish Arora (Advisor); Shaileshh Bojja Venkatakrishnan (Committee Member); Kannan Athreya (Committee Member); Ness Shroff (Committee Member) Subjects: Computer Science

Master of Science in Electrical Engineering, Cleveland State University, 2021, Washkewicz College of Engineering

In this thesis, we draw attention to the problem of cross-service attacks, that is, attacks that exploit information collected about users from one service to launch an attack on the same users on another service. With the increased deployment and use of what fundamentally are integrated-services networks, such as 4G/LTE networks and now 5G, we expect that cross-service attacks will become easier to stage and therefore more prevalent. As running example to illustrate the effectiveness and the potential impact of cross-service attacks we will use the problem of account association in 4G/LTE networks. Account association attacks aim at determining whether a target mobile phone number is associated with a particular online account. In the case of 4G/LTE, the adversary launches the account association attacks by sending SMS messages to the target phone number and analyzing patterns in traffic related to the online account. We evaluate the proposed attacks in both a local 4G/LTE testbed and a major commercial 4G/LTE network. Our extensive experiments show that the proposed attacks can successfully identify account association with close-to-zero false negative and false positive rates. Our experiments also illustrate that the proposed attacks can be launched in a way that the victim receives no indication of being under attack.

Committee: Ye Zhu (Committee Chair); Yongjain Fu (Committee Member); Sui-Tung Yau (Committee Member) Subjects: Computer Engineering; Computer Science; Electrical Engineering; Information Technology; Technology

Doctor of Philosophy, The Ohio State University, 2021, Electrical and Computer Engineering

In applications such as networked monitoring and control systems, wireless sensor networks, and autonomous vehicles, it is crucial for the destination node to receive timely status updates so that it can make accurate decisions. For example, a moving car with a speed of 65 mph will traverse almost 29 meters in 1 second, and hence, stale information (regarding the location of surrounding vehicles, velocities, etc.) has a dramatic serious impact on this situation. Age of information (AoI), or simply age, has been used to measure the freshness of status updates. More specifically, AoI is the age of the freshest update at the destination, i.e., it is the time elapsed since the freshest received update was generated. It should be noted that optimizing traditional network performance metrics, such as throughput or delay, does not attain the goal of timely updating. For instance, it is well known that AoI could become very large when the offered load is high or low. In other words, AoI captures the information lag at the destination, and is hence more apt for achieving the goal of timely updates. In this thesis, we leverage rigorous theory to develop low-complexity scheduling algorithms that are apt for a wide range of information update systems. In particular, we consider the following systems: -Information update systems with stochastic packet arrivals: We consider single and multihop networks with stochastic arrivals, where our goal is to answer the following fundamental questions: (i) Which queueing discipline can minimize the age? And (ii) under what conditions is the minimum age achievable? Towards this goal, we design low-complexity scheduling policies to achieve (near) age-optimality in single and multihop networks with single source. The achieved results that we present here hold under quite general conditions, including (i) arbitrary packet generation and arrival processes, (ii) for minimizing both the age processes in stochastic ordering and any non-d (open full item for complete abstract)

Committee: Ness Shroff (Advisor); Yin Sun (Other); Atilla Eryilmaz (Committee Member); Abhishek Gupta (Committee Member); Qin Ma (Committee Member) Subjects: Communication; Computer Engineering; Electrical Engineering

Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee: Not Provided (Other) Subjects: Computer Science

Master of Science (M.S.), University of Dayton, 2015, Electrical Engineering

Intrusion Detection Systems (IDS) are intelligent specialized systems designed to interpret intrusion attempts from incoming network traffic. IDSs aim at minimizing the risk of accessing unauthorized data and potential vulnerabilities in critical systems by examining every packet entering a system. Packet inspection and Pattern matchings are often computationally intensive processes and that are the most power hungry functionalities in network intrusion detection systems. This thesis presents a high throughput, low latency and low power memristor crossbar architecture for packet header and payload matching that could be used for high-speed packet classification and malware detection. The memristor crossbar systems can perform intrusion detection through a brute force approach for static contents/signatures and a state machine approach for regular expressions. A large portion of the work completed in this thesis has been published in [1-2].

Committee: Tarek Taha Dr (Advisor); Eric Balster Dr (Committee Member); Vamsy Chodavarapu Dr (Committee Member) Subjects: Computer Engineering; Electrical Engineering

Master of Information and Telecommunication Systems (MITS), Ohio University, 2015, Information and Telecommunication Systems (Communication)

This thesis proposes a compensation mechanism for maintaining the quality of experience (QoE) when a user controls a ground vehicle over a wireless link affected by packet losses. This research is important because it applies to many relevant areas such as remote surgery, and search and rescue operations in human unfriendly environments. Previous research focused on quantifying network parameters, and using a delay tolerant network (DTN) approach to compensate for packet losses. This study proposes a different approach by using a heuristic based algorithm that tracks packet losses and then decides a course of action based on the current state of the system. Such a strategy helps reduce the mean time to complete tasks (TTCT) by approximately 16, 29, 36 and 90% when the link condition is in the good, medium, bad, and worst condition respectively. The system is successfully tested via a human-based experimental study by approximately 60 participants.

Committee: Julio Arauz PhD (Advisor); Hans Kruse PhD (Committee Member); Andy Snow PhD (Committee Member) Subjects: Communication; Computer Science; Electrical Engineering; Robotics

Master of Science (MS), Wright State University, 2014, Earth and Environmental Sciences

Wright State University acquired two vibroseis-sourced seismic reflection lines over the Dominion East Ohio Gabor Gas Storage field near Canton, Ohio. The data were gathered over a fully charged reservoir within the Clinton interval. Seismic attributes were applied to the seismic data for interpretation. The seismic response of nearby wells was modeled for comparison with the seismic lines. Within the seismic data a gas shadow was observed. The gas shadow coincides with an area of high initial production of wells targeting the Clinton interval for production. The gas shadow is also associated with broadening of the Packer Shell sidelobe. Modelling of the seismic response of well API# 3416925010000 shows a broadening effect of the Packer Shell sidelobe similar to that seen in the seismic data. This broadening is also associated with low porosity, implying that broadening of the Packer Shell sidelobe is indicative of a poor hydrocarbon reservoir.

Committee: Doyle Watts Ph.D. (Committee Chair); Ernest Hauser Ph.D. (Committee Member); David Dominic Ph.D. (Committee Member) Subjects: Earth; Energy; Geology; Geophysics; Petroleum Geology

Master of Science (M.S.), University of Dayton, 2014, Electro-Optics

We measured the three-dimensional (3D) propagation dynamics of the Airy-Bessel wave packet, inculding its intensity and phase evolution. Its non-diffraction and non-dispersive feature were verified. Meanwhile, we built a spatial-light-modulator (SLM) based wave packet shaping system to generate other types of wave packets such as Airy-Airy-Airy and dual-Airy-Airy-rings. These wave packets were also measured in 3D. The abrupt 3D autofocusing effect was observed on dual-Airy-Airy-rings.

Committee: Andy Chong (Advisor); Joseph Haus (Committee Member); Partha Banerjee (Committee Member) Subjects: Electromagnetism; Optics; Physics

PhD, University of Cincinnati, 2007, Engineering : Computer Science and Engineering

Recent years have witnessed an extensive proliferation of wireless technology in every domain of day-to-day life. Examples include mobile phones, broadband communication, wireless LAN, wireless enabled PDAs, cordless phones, garage-door openers and the list continues. Advancements in radio technology, antenna technology, low power computational digital signal processing (DSP) and micro-electro-mechanical systems (MEMS) are instrumental in reducing the size and cost of wireless devices. A wireless network consists of wireless devices forming an infrastructure-based or a peer-to-peer network. A network can be a single-hop or multihop network. Single-hop networks are already in existence and have been substantially investigated. This dissertation thus focuses on multihop wrireless networks, where the intermediate wireless devices also act as routers. Depending on their functionality, multihop wireless networks can be categorized into ad hoc, mesh and sensor networks. A mobile ad hoc network (MANET) aims at provding a mobile network with connectivity similar to a wired network without the need for any infrastructure support. A wireless mesh network (WMN) typically extends the infrastructure based single hop wireless network and has become a new paradigm for providing last mile broadband access. A wireless sensor network (WSN) is similar to an ad hoc network, providing a cheap alternative to monitoring applications. Each of these multihop wireless networks has their own set of challenges with respect to operation and implementation. The first part of this dissertation focuses on developing on-demand medium access control (MAC) protocols for multiple beam smart antennas (MBSAs) in ad hoc and mesh environments. MBSA has the unique capability of simultaneously initiating packet transmissions or receptions in multiple beams. Thus, compared to traditional omnidirectional antennas, MBSA can better utilize the spatial bandwidth, thereby increasing the capacity of wireless netwo (open full item for complete abstract)

Committee: Dr. Dharma Agrawal (Advisor) Subjects: Computer Science

PhD, University of Cincinnati, 2004, Engineering : Electrical Engineering

As demand for higher data rates is continuously rising, there is always a need to develop more efficient wireless communication systems. The work described in this thesis is our effort in this direction. We have developed and evaluated a wavelet packet based multicarrier CDMA wireless communication system. In this system design a set of wavelet packets are used as the modulation waveforms in a multicarrier CDMA system. The need for cyclic prefix is eliminated in the system design due to the good orthogonality and time-frequency localization properties of the wavelet packets. New detection algorithms are developed to work in either time domain or wavelet packet domain to combat multiuser and inter symbol interferences. Better performance is achieved by utilizing the saved cyclic prefix overhead for error correction coding. In developing the above system and detection algorithms, we also explored a new method of channel modeling by using wavelet packets as basis functions.

Committee: Dr. Howard Fan (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2011, Food, Agricultural and Biological Engineering

Industrial applications of ohmic heating are mainly limited to continuous thermal processing of food. Main objectives of this research were to explore its applications in a batch type container, and investigate additional non thermal effects of electric field on bacterial spores, enzymes, carotenoids, flavonoids and quality parameters in food. An ohmic packet made up of multilayered laminate material and capable of sterilizing food was developed. A pouch design optimization exercise was conducted to improve the heating profile and integrity of the hermetic seal at temperature and pressure conditions associated with a sterilization process. A simulation study in 3D was done for sterilization in the ohmic pouch. The mathematical model and sterilization were validated through an inoculated pack study using Geobacillus stearothermophilus spores. Non thermal effects of electricity at frequencies of 10 kHz and 60 Hz during ohmic heating were studied on thermophilic bacterial spores of G. stearothermophilus and Bacillus coagulans. A precise capillary sized ohmic device was invented to eliminate potential source of experimental errors, and to obtain identical time temperature histories for both ohmically and conventionally heated samples. Ohmic heating at both frequencies were found to accelerate inactivation of bacterial spores. It was hypothesized that release of polar dipicolinic acid molecules and spore proteins at higher temperature conditions and their vibrations under the external electric field have resulted in an accelerated inactivation. A linearly increasing temperature analysis of the B. coagulans data suggested that Z values obtained at isothermal conditions may only be valid over a narrow range of temperature. Effects of ohmic heating on pectin methylesterase (PME) and polygalacturonase (PG) enzymes were evaluated in fresh tomato juice at pH of 3.9 and 4.4. PME at pH 3.9 showed a high variability in the inactivation data possibly due to the interaction of (open full item for complete abstract)

Committee: Sudhir K. Sastry (Advisor); Gonul Kaletunc (Committee Member); V. M. Balasubramaniam (Committee Member) Subjects: Agricultural Engineering; Food Science

Doctor of Philosophy, The Ohio State University, 2005, Computer and Information Science

Among different wireless technologies, wireless ad hoc networks and cellular networks account for a large part of wireless communications. In this work, we take an extensive study at the management of the two of very important resources in both wireless ad hoc networks and cellular networks: power and code (bandwidth). In the first part, we focus on the power management in IEEE 802.11 ad hoc networks. We first aim at the mismatch between the power management protocol and the ever-increasing transfer rate. We propose modifications on the power management operations of IEEE 802.11 which introduce very little overhead but bring a big boost on the performance in both power efficiency and data throughput by combining a scheduling algorithm with the power management. Then, we concentrate on the new challenges faced by the power and synchronization protocols when pushing the IEEE 802.11 ad hoc mode into the multi-hop environment. We study the relationship between clock synchronization and power management in Mobile Multi-hop Ad Hoc Network (MANET). After reaching the conclusion that clock synchronization is vital for not only efficient power management, but many other network operations as well, we present a protocol to generate a globally synchronous system from synchronized sub-networks. We discuss the correctness of the protocol, and show the power efficiency brought by such a synchronous system in simulations. Lastly, we present a framework, which takes advantage both of the two main approaches in energy conservation, i.e. power management and power control, to maximize power-saving. Because the goals that each scheme seeks contradict each other, we study the balance and the trade-off between them, and use them as the guideline on building our framework. In the second part of this work, we shift to the code (bandwidth) assignment for multimedia traffic in Code Division Multiple Access (CDMA) networks. We propose several algorithms to handle the jitters of compressed vi (open full item for complete abstract)

Committee: Ming Liu (Advisor); Ten-Hwang Lai (Other); Dong Xuan (Other) Subjects: Computer Science

Master of Science (MS), Ohio University, 1991, Electrical Engineering & Computer Science (Engineering and Technology)

Congestion control using saturation feedback for multihop packet radio networks

Committee: Jeffrey Dill (Advisor) Subjects:

Master of Science (MS), Ohio University, 1990, Electrical Engineering & Computer Science (Engineering and Technology)

Use of finite random graphs to model packet radio networks

Committee: Jeffrey Dill (Advisor) Subjects:

Doctor of Philosophy (PhD), Ohio University, 2000, Electrical Engineering & Computer Science (Engineering and Technology)

In this dissertation, a novel wavelet packet based multicarrier modulation CDMA system is proposed and analyzed. Properties of wavelets and wavelet packets are investigated, the concept of wavelet packet modulation is then explained. Based on this concept, a wavelet packet based multicarrier modulation CDMA transceiver structure is proposed. Compared with three conventional sinusoids based multicarrier CDMA systems, the proposed system has the same computation complexity, consumes much less system resource while achieves the same performance and system capacity. System performance of the proposed system are investigated in two different channels. In the AWGN channel, two anti-jamming algorithms are developed for the proposed system. First, the simplified super-symbol tuning algorithm for known jamming suppression is developed. By taking advantage of the knowledge of the system and jamming signal, the one-direction tuning algorithm can achieve the same performance as the algorithm using both forward and reverse tuning, therefore, greatly simplifies the system. Second, in a system with unknown narrow band jamming signals, generalized Fisher's test algorithm is developed. Due to the time-frequency compact support property of wavelet packets, narrow band jamming signal can be easily detected by using wavelet packet transform and inverse transform pair. Numerical results show that generalized Fisher's test algorithm can suppress the jamming signal in a large jamming to noise ratio range with large jamming signal bandwidth variation. In the slow fading frequency selective channel, maximal ratio combining and equal gain combing equalization techniques under both synchronous and asynchronous situations are investigated. From both theoretical analysis and numerical result, it is shown that maximal ratio combining equalization outperforms the equal gain combining equalization. Based on all the analysis and results, it is clear that wavelet packet based multi-carrier modulatio (open full item for complete abstract)

Committee: Jeffrey Dill (Advisor) Subjects:

Master of Science (MS), Ohio University, 1993, Electrical Engineering & Computer Science (Engineering and Technology)

Performance analysis of routing algorithms of RD-C/TDMA packet radio networks under dynamic random topology

Committee: J. Dill (Advisor) Subjects: